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From: Saeed Mahameed <saeed@kernel•org>
To: "David S. Miller" <davem@davemloft•net>,
	Jakub Kicinski <kuba@kernel•org>, Paolo Abeni <pabeni@redhat•com>,
	Eric Dumazet <edumazet@google•com>
Cc: Saeed Mahameed <saeedm@nvidia•com>,
	netdev@vger•kernel.org, Moshe Shemesh <moshe@nvidia•com>,
	Leon Romanovsky <leonro@nvidia•com>
Subject: [PATCH net-next 1/9] net/mlx5: Remove devl_unlock from mlx5_eswtich_mode_callback_enter
Date: Mon, 11 Jul 2022 01:14:00 -0700	[thread overview]
Message-ID: <20220711081408.69452-2-saeed@kernel.org> (raw)
In-Reply-To: <20220711081408.69452-1-saeed@kernel.org>

From: Moshe Shemesh <moshe@nvidia•com>

The function mlx5_eswtich_mode_callback_enter() was added as a temporary
workaround once devlink instance lock was added to devlink eswitch
callbacks. However, code review and testing show that all the callbacks
part to eswitch_mode_set don't take devlink instance lock in any flow
and so unlocking devlink instance lock while entering these functions is
not needed.

Remove devl_lock from mlx5_eswtich_mode_callback_enter() and devl_unlock
from mlx5_eswtich_mode_callback_exit(). Also remove the functions
mlx5_eswtich_mode_callback_enter()/exit() as they are not needed any
more. The callback eswitch_mode_set will be treated separately in the
following patches.

Signed-off-by: Moshe Shemesh <moshe@nvidia•com>
Reviewed-by: Leon Romanovsky <leonro@nvidia•com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia•com>
---
 .../mellanox/mlx5/core/eswitch_offloads.c     | 43 +++++--------------
 1 file changed, 11 insertions(+), 32 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
index e224ec7005a6..3bd843e6d66a 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
@@ -3342,27 +3342,6 @@ static int esw_inline_mode_to_devlink(u8 mlx5_mode, u8 *mode)
 	return 0;
 }
 
-/* FIXME: devl_unlock() followed by devl_lock() inside driver callback
- * is never correct and prone to races. It's a transitional workaround,
- * never repeat this pattern.
- *
- * This code MUST be fixed before removing devlink_mutex as it is safe
- * to do only because of that mutex.
- */
-static void mlx5_eswtich_mode_callback_enter(struct devlink *devlink,
-					     struct mlx5_eswitch *esw)
-{
-	devl_unlock(devlink);
-	down_write(&esw->mode_lock);
-}
-
-static void mlx5_eswtich_mode_callback_exit(struct devlink *devlink,
-					    struct mlx5_eswitch *esw)
-{
-	up_write(&esw->mode_lock);
-	devl_lock(devlink);
-}
-
 int mlx5_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode,
 				  struct netlink_ext_ack *extack)
 {
@@ -3431,9 +3410,9 @@ int mlx5_devlink_eswitch_mode_get(struct devlink *devlink, u16 *mode)
 	if (IS_ERR(esw))
 		return PTR_ERR(esw);
 
-	mlx5_eswtich_mode_callback_enter(devlink, esw);
+	down_write(&esw->mode_lock);
 	err = esw_mode_to_devlink(esw->mode, mode);
-	mlx5_eswtich_mode_callback_exit(devlink, esw);
+	up_write(&esw->mode_lock);
 	return err;
 }
 
@@ -3480,7 +3459,7 @@ int mlx5_devlink_eswitch_inline_mode_set(struct devlink *devlink, u8 mode,
 	if (IS_ERR(esw))
 		return PTR_ERR(esw);
 
-	mlx5_eswtich_mode_callback_enter(devlink, esw);
+	down_write(&esw->mode_lock);
 
 	switch (MLX5_CAP_ETH(dev, wqe_inline_mode)) {
 	case MLX5_CAP_INLINE_MODE_NOT_REQUIRED:
@@ -3514,11 +3493,11 @@ int mlx5_devlink_eswitch_inline_mode_set(struct devlink *devlink, u8 mode,
 		goto out;
 
 	esw->offloads.inline_mode = mlx5_mode;
-	mlx5_eswtich_mode_callback_exit(devlink, esw);
+	up_write(&esw->mode_lock);
 	return 0;
 
 out:
-	mlx5_eswtich_mode_callback_exit(devlink, esw);
+	up_write(&esw->mode_lock);
 	return err;
 }
 
@@ -3531,9 +3510,9 @@ int mlx5_devlink_eswitch_inline_mode_get(struct devlink *devlink, u8 *mode)
 	if (IS_ERR(esw))
 		return PTR_ERR(esw);
 
-	mlx5_eswtich_mode_callback_enter(devlink, esw);
+	down_write(&esw->mode_lock);
 	err = esw_inline_mode_to_devlink(esw->offloads.inline_mode, mode);
-	mlx5_eswtich_mode_callback_exit(devlink, esw);
+	up_write(&esw->mode_lock);
 	return err;
 }
 
@@ -3549,7 +3528,7 @@ int mlx5_devlink_eswitch_encap_mode_set(struct devlink *devlink,
 	if (IS_ERR(esw))
 		return PTR_ERR(esw);
 
-	mlx5_eswtich_mode_callback_enter(devlink, esw);
+	down_write(&esw->mode_lock);
 
 	if (encap != DEVLINK_ESWITCH_ENCAP_MODE_NONE &&
 	    (!MLX5_CAP_ESW_FLOWTABLE_FDB(dev, reformat) ||
@@ -3592,7 +3571,7 @@ int mlx5_devlink_eswitch_encap_mode_set(struct devlink *devlink,
 	}
 
 unlock:
-	mlx5_eswtich_mode_callback_exit(devlink, esw);
+	up_write(&esw->mode_lock);
 	return err;
 }
 
@@ -3605,9 +3584,9 @@ int mlx5_devlink_eswitch_encap_mode_get(struct devlink *devlink,
 	if (IS_ERR(esw))
 		return PTR_ERR(esw);
 
-	mlx5_eswtich_mode_callback_enter(devlink, esw);
+	down_write(&esw->mode_lock);
 	*encap = esw->offloads.encap;
-	mlx5_eswtich_mode_callback_exit(devlink, esw);
+	up_write(&esw->mode_lock);
 	return 0;
 }
 
-- 
2.36.1


  reply	other threads:[~2022-07-11  8:14 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-11  8:13 [PATCH net-next 0/9] mlx5 devlink mutex removal part 1 Saeed Mahameed
2022-07-11  8:14 ` Saeed Mahameed [this message]
2022-07-11  8:14 ` [PATCH net-next 2/9] net/mlx5: Use devl_ API for rate nodes destroy Saeed Mahameed
2022-07-11  8:14 ` [PATCH net-next 3/9] devlink: Remove unused function devlink_rate_nodes_destroy Saeed Mahameed
2022-07-11  8:14 ` [PATCH net-next 4/9] net/mlx5: Use devl_ API in mlx5_esw_offloads_devlink_port_register Saeed Mahameed
2022-07-11  8:14 ` [PATCH net-next 5/9] net/mlx5: Use devl_ API in mlx5_esw_devlink_sf_port_register Saeed Mahameed
2022-07-11  8:14 ` [PATCH net-next 6/9] devlink: Remove unused functions devlink_rate_leaf_create/destroy Saeed Mahameed
2022-07-11  8:14 ` [PATCH net-next 7/9] net/mlx5: Use devl_ API in mlx5e_devlink_port_register Saeed Mahameed
2022-07-11  8:14 ` [PATCH net-next 8/9] net/mlx5: Remove devl_unlock from mlx5_devlink_eswitch_mode_set Saeed Mahameed
2022-07-11  8:14 ` [PATCH net-next 9/9] devlink: Hold the instance lock in port_new / port_del callbacks Saeed Mahameed
2022-07-12  3:03 ` [PATCH net-next 0/9] mlx5 devlink mutex removal part 1 Jakub Kicinski
2022-07-12  8:50 ` patchwork-bot+netdevbpf

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